1. Field of the Invention
The present invention relates to a vibration generation apparatus for a game machine operation unit.
2. Description of the Related Art
Referring to FIG. 10, a conventional vibration apparatus is described below.
The conventional apparatus is made of a columnar direct-current (DC) motor 51 having an eccentric rotating mass 52, such as a weight in the form of a segment or a semicircular disc, on a rotation axis 51a thereof. In such a construction of the conventional vibration generation apparatus, DC voltage is provided from a power source (not shown) to power terminals 51b of the DC motor 51 so that vibration occurs.
When DC voltage is applied and the DC motor 51 rotates, the eccentric rotating mass 52, disposed on the rotation axis 51a, generates centrifugal force causing the entire DC motor 51 to vibrate.
In such a conventional vibration generation apparatus, however, when the speed of the DC motor rotation is increased, the centrifugal force caused by the eccentric rotating mass 52 is proportionally increased; the amplitude is thereby also increased so that frequency and amplitude cannot be controlled independently of each other. Because of this problem, game machine operations are limited in regard to the production of a variety of vibration modes to provide adequate simulation effects.